The present invention relates to a self contained constant pressure applied proximally (CPAP) device and to a system and method which prevent collapse of the upper airway. More particularly, the present invention relates to the use thereof for treatment of breathing disorders including, but not limited to, obstructive sleep apnea (OSA), apnea of infancy (AOI) and sudden infant death syndrome (SIDS).
OSA is a syndrome with significant morbidity and mortality (C. Guilleminault and M. Partinen (eds.) (1990) xe2x80x9cObstructive Sleep Apnea Syndrome: Clinical; Research and Treatmentxe2x80x9d. Raven Press, New York, N.Y., USA, pp xv-xvii). OSA is caused by repeated collapse of soft tissues forming the walls of the upper airway in the sub-glottal region during sleep (C. Guilleminault and M. Partinen, Ibid.). Opening of this portion of the airway depends upon the balance between negative pressure, which is at least xe2x88x927 or xe2x88x9210 cm H2O in normal quiet breathing (Levitzki MG (eds)(1986) xe2x80x9cPulmonary Physiologyxe2x80x9d McGrawxe2x80x94Hill Book Company, New York, N.Y., USA pp 37-40) outside the cavity caused by muscular action during breathing (e.g. action of the diaphragm and muscles surrounding the rib cage) and muscle tone in the upper airway itself (C. E. Sullivan et al., in C. Guilleminault and M. Partinen, Ibid., pp 49-69; S. T. Kuna et al. (1991) JAMA 266:1384-1389; J. E. Remmers et al., (1978) J. Appl. Physiol. 44:931-938; and D. J. Tangel et al. (1991) J. Appl. Physiol. 70:2574-2581). This repeated collapse of the upper airway causes a decrease in blood oxygen saturation which leads to sleep disturbances, fatigue and a general feeling of malaise in affected patients.
OSA is a common disorder with an estimated 2% of women and 4% of men being affected to a degree that treatment is advisable. This means that an estimated 12 to 18 million patients are affected in the USA. Since only about 7 to 18% of the population has been tested for this disorder, these estimates should be viewed as minimum estimates (C. Guilleminault in C. Guilleminault and E. Largesi (eds.) (1983) Raven Press, New York, N.Y., USA, pp 107-125; M. Partinen et al. (1988) Chest 94: 1200-1204; J. JE et al. (1988) Chest 94:9-14; National Commission on Sleep Disorders Research (1995) xe2x80x9cWake Up America: A National Sleep Alertxe2x80x9d U.S. Government Printing Office, Washington, D.C., USA, pp 2-10; T. Young et al. (1997) Sleep 20:705-706).
Currently accepted treatment for OSA typically includes continuous positive airway pressure (CPAP). CPAP, as currently practiced, involves connection of a pressurized air delivering device to the mouth or nose of the patient. This device typically is connected to a pressurized air source in the form of a compressor or tank with a regulator. These pressurized air supplies are expensive, large, and noisy.
Delivery of a constant flow of a breathable gas mixture through the device maintains a constant positive pressure in the upper airway. This constantly applied pressure prevents the collapse of the airway described hereinabove(C. E. Sullivan et al. (1981) Lancet 1:862-865; M. H. Sanders et al. (1983) Chest 83:144-145). CPAP is effective in treating OSA by preventing collapse of the airway and associated tiredness, fatigue, diminished intellectual function, and snoring and can even lengthen patient life expectancy (J. Hender et al. (1995) Eur. Respir. J. 8:222-229; H. Minemura et al. (1998) Intern. Med. 37: 1009-1013; C. Jenkinson et al. (1999) Lancet 353: 2100-2105).
In order to keep the pressure in the airway constant during inhalation and exhalation, a pressure valve is sometimes incorporated into the pressurized air delivering device. One such valve is taught by U.S. Pat. No. 4,298,023 for a spring loaded exhalation valve. Teachings of this patent specifically relate to treatment regimens which include a flow of gas delivered to the airway from a pressurized air supply.
However, patient compliance with CPAP treatment regimens is typically poor despite the proven efficacy of the treatment. Research suggests that 60 to 70% compliance is the norm and that the average patient use of CPAP is limited to 5 hours per night (N. P. Kribbs et al. (1993) Am. Rev. Respir. Dis. 147:887-895; H. Rauscher et al. (1993) Chest 103:1675-1680). In addition, many patients never begin treatment at all owing to the high cost of CPAP equipment.
Infants are typically obligatory nasal breathers (Shannon DC In: Disorders of the Respiratory Tract In Children- SIDS and Apnea in infancy Kendig and Chemick eds (1990) W. B. Saunders Company, Philadelphia, Pa., USA pp 939-952.). Any change in airflows in the upper airways increase vulnerability to inadequate ventilation because: (1). the hypopharynx is shallow; (2) the tongue and epiglottis are more cephaled and (3) the mandible is more mobile (Tonkin S.(1975) Pediatrics 55:650-654). Normal infants typically have difficulty responding to nasal occlusion. Studies show that 44% of 6 week old infants struggled but failed to establish an oral airway when the nostrils were pinched for 25 seconds (Swift PGF et al (1973) Arch Dis Child 48:947-950). The physiologic basis for the failure to maintain adequate oral ventilation during occlusion in both normal and at risk infants is unknown. This mechanism has been suggested as a cause of AOI which can lead to SIDS (Anderson R B et al (1971) Biol Neonate 18:395-398.
There is thus a widely recognized need for, and it would be highly advantageous to have, a device, system and method which prevent collapse of the upper airway devoid of the above limitation.
According to one aspect of the present invention there is provided a self contained CPAP device. The device comprises; (a) a mouthpiece insertable in a mouth of a patient; (b) a breathing tube connecting between an outside environment and an interior of the mouth, the breathing tube containing at least one bi-directional pressure sensitive valve therein; (c) at least one inflatable body, the inflatable body functioning to adjust an internal cross sectional area of the breathing tube during a process of respiration, the inflatable body further serving to regulate an air pressure within the mouth during the process of respiration; and (d) a mask, the mask being in fluid communication with the inflatable body and being designed and constructed to cover a nose of the patient, such that exhaled air is routed thereto.
According to another aspect of the present invention there is provided a system for prophylactic treatment of a breathing disorder, the system comprising a self contained CPAP device, the device being designed and constructed to: (a) maintain sufficient pressure in an upper airway of a patient such that collapse thereof is prevented; and (b) function independently of any item selected from the group consisting of a pump, a compressor, a pressurized gas cylinder and an electro-hydrolytic oxygen source.
According to yet another aspect of the present invention there is provided an improved method of preventing a breathing disorder by means of CPAP, the method comprising the steps of: (a) inserting a mouthpiece in a mouth of a patient; (b) allowing inhaled air to flow through at least one bidirectional pressure sensitive valve contained within a breathing tube connecting between an outside environment and an interior of the mouth; (c) adjusting an internal cross sectional area of the breathing tube during a process of respiration by means of at least one inflatable body, the at least one inflatable body serving to regulate an air pressure within the mouth during the process of respiration and (d) covering a nose of the patient with a mask, the mask being in fluid communication with the at least one inflatable body and being designed and constructed to receive exhaled air therefrom and route the exhaled air to the nose of the patient.
According to further features in preferred embodiments of the invention described below, the at least one inflatable body comprises: (i) at least one elastic balloon; (ii) at least one first additional unidirectional pressure sensitive valve in communication an interior of the breathing tube; and (iii) at least one second additional unidirectional pressure sensitive valve in communication with an exhaled air tube, the exhaled air tube being in communication with the mask;
According to still further features in the described preferred embodiments the at least one inflatable body comprises any number of inflatable bodies having a total inflated volume which is approximately 120 to 350 ml greater than a total deflated volume thereof such that it is suitable for use in adults.
According to still further features in the described preferred embodiments the at least one inflatable body comprises any number of inflatable bodies having a total inflated volume which is approximately 40 to 160 ml greater than a total deflated volume thereof such that it is suitable for use in children. According to still further features in the described preferred embodiments the at least one inflatable body comprises any number of inflatable bodies having a total inflated volume which is approximately 2 to 40 ml greater than a total deflated volume thereof such that it is suitable for use in infants.
According to still further features in the described preferred embodiments the at least one inflatable body comprises any number of inflatable bodies having a total inflated volume which is approximately 2 to 4 ml greater than a total deflated volume thereof for each Kg of mass of said patient.
According to still further features in the described preferred embodiments the inflatable body further comprises at least one undirectional pressure sensitive safety valve in communication with the outside environment, the safety valve functioning to prevent explosion of the at least one inflatable body.
According to still further features in the described preferred embodiments the safety valve opens when a predetermined volume is exceeded.
According to still further features in the described preferred embodiments the mouthpiece is adjustable to fit the mouth of the patient.
According to still further features ID the described preferred embodiments there is provided a mechanism for facilitating inflation of the mouthpiece.
According to still further features in the described preferred embodiments there is provided a mechanism for sealing between the mouthpiece and lips of the patient, such that airflow between the lips and the mouthpiece is diminished
According to still further features in the described preferred embodiments the device further comprises a chin holder having a first end which is capable of engaging a chin of the patient and a second end which is connectable to the device.
According to still further features in the described preferred embodiments the breathing tube passes through the mouthpiece
According to still further features in the described preferred embodiments the device further comprises at least one retaining piece for holding the device in place.
According to still further features in the described preferred embodiments the at least one retaining piece includes at least one item selected from the group consisting of at least one strap, at least one elastic band, at least one piece of Velcro(trademark) and a pair of protrusions which engage the ears of the patient.
According to still further features in the described preferred embodiments the device further comprises a filter in the breathing tube, the filter designed and constructed to prevent the entry of foreign bodies thereto.
According to still further features in the described preferred embodiments the device is designed and configured for a purpose selected from the group consisting of treating obstructive sleep apnea, treating apnea of infancy and preventing sudden infant death syndrome.
According to still further features in the described preferred embodiments the device comprises: (i) a mouthpiece insertable in a mouth of a patient; (ii) a breathing tube connecting between an outside environment and an interior of the mouth, the breathing tube containing at least one bidirectional pressure sensitive valve therein; (iii) an inflatable body, the inflatable body functioning to adjust an internal cross sectional area of the breathing tube during a process of respiration, the at least one inflatable body further serving to regulate an air pressure within the mouth during the process of respiration; and (iv) a mask, the mask being in fluid communication with the at least one inflatable body and being designed and constructed to cover a nose of the patient, such that exhaled air is routed thereto.
According to still further features in the described preferred embodiments the at least one inflatable body comprises: (i) at least one elastic balloon; (ii) at least one first additional unidirectional pressure sensitive valve in communication an interior of the breathing tube; and (iv) at least one second additional unidirectional pressure sensitive valve in communication with an exhaled air tube, the exhaled air tube being in communication with the mask. This configuration assures that exhaled air passes through the first additional unidirectional pressure sensitive valve, thereby inflating the at least one inflatable body and causing an elevated pressure to form therein and that reducing of the elevated pressure is accomplished by a release of exhaled air through the second additional unidirectional pressure sensitive valve.
According to still further features in the described preferred embodiments there is provided at least one unidirectional pressure sensitive safety valve in communication with the outside environment such that exploding of the at least one inflatable body is prevented by release of the exhaled air through the safety valve when the elevated pressure exceeds a predefined limit.
According to still further features in the described preferred embodiments the method comprises the additional step of adjusting the mouthpiece to fit the mouth of the patient.
According to still further features in the described preferred embodiments the step of adjusting is accomplished by inflating the mouthpiece.
The present invention successfully addresses the shortcomings of the presently known configurations by providing a CPAP device which is small, lightweight, portable, and relies primarily upon exhaled air as a source of pressure.